This invention relates to articulated master slave manipulators, and is particularly directed to manipulators of the type having counter-balance masses, with motor actuating means in the counter-balance masses for controlling the rotation of output pulleys in a lower arm.
A manipulator of this type is disclosed, for example, in U.S. Pat. No. 3,790,002, Germond et al. In the arrangement of this reference, the lower arm is pivoted to the upper arm at an axis on which idler pulleys are arranged, however, the counter-balance mass is pivoted to the upper arm about an axis displaced from the axis of the idler pulleys in the other end of the upper arm. In this reference the flexible tapes extending between the actuator in the counter-balance mass and the lower arm pass the upper sides of the two idler pulleys.
In the provision of a manipulator of this type, it is desirable to maintain the tape or cable extending between the actuator and the output pulley under uniform tension at all times, in order to assure the reversibility and accuracy of the transmission of motion between the actuator and the output pulley. It is further desirable to arrange the elements so that the counter-balance mass continually accurately counter-balances the lower arm. The arrangement of the above described Germond et al patent has not been found to attain these objectives in the mose desirable manner. Various other arrangements have been provided for controlling the rotation of an output pulley in a manipulator system. For example, such systems are shown in U.S. Pat. No. 2,774,488 (Goertz et al) and U.S. Pat. No. 3,572,807 (Haaker et al). In these arrangements, as in the above mentioned Germond et al patent, the flexible cable or tape also extends over the tops of the two main idler pulleys in the upper arm, and the pivotal axes of at least one of the arms affixed to the upper arm is not positioned at the respective main idler pulley. As a consequence, such arrangements also have the disadvantages of the above discussed Germond et al patent. Similarly, U.S. Pat. No. 3,314,552 (Vertut) and U.S. Pat. No. 3,664,517 (Germond et al) also disclose manipulator systems in which the flexible cable or tape extends over the tops of the main idler pulleys. A number of the above systems have the further disadvantage that their usefulness is reduced in the provision of a large number of idler pulleys, and in the provision of relatively complex control systems.